The religious leader praises President Bashar Assad the day after the deadly attack. Meanwhile, urban battles and assassinations lead some to warn that a new and bloodier chapter may be beginning.

Reporting from Beirut — The Syrian government on Monday blamed "terrorist" attackers for killing the son of a prominent Sunni Muslim cleric and declared that its forces had seized a large number of weapons near the Turkish border.

The developments come as the strategically situated Arab country suffers a wave of what appear to be targeted assassinations and intense urban battles, some reportedly involving army defectors.

There are fears that the unrest, inspired in part by "Arab Spring" protests elsewhere in the region, may be the start of a new and bloodier chapter in Syria's violence.

On Sunday, a broad-based new opposition council accused President Bashar Assad of "a policy of sectarian incitement" that "is pushing the country to the brink of civil war."

The Syrian National Council, an umbrella organization of the disparate opposition groups, urged the use of peaceful means to topple Assad, and rejected any foreign intervention or military force to bring about change.

However, reports from Syria have indicated that both defectors and other antigovernment activists may have in some cases taken up arms. They remain heavily outgunned by the government's artillery, tanks and other equipment.

"This is a critical juncture," said Amr Azm, an associate professor of Middle East Studies at Shawnee State University in Ohio, who is a member of the opposition council. "The street has bled profusely in these protests. There is only so far they can go. There has to be some give, some shift soon, that pushes the uprising to more of a military, armed conflict, or it escalates in a different direction."

Formal creation of the opposition council, announced in Istanbul, Turkey, came as the government said it had regained control of the rebellious central city of Rastan, where activists said troops fought army defectors in the first protracted armed confrontation since Syria's upheaval began in March. Antigovernment activists reported Monday that the regime had arrested several thousand in Rastan, just north of Homs.

Recent targeted assassinations in Homs have raised the specter of sectarian vendettas and score-settling.

On Monday, the government also said it had seized scores of pump-action shotguns, Kalashnikov assault rifles, rocket-propelled grenades and other arms in the city of Idlib, near the Turkish border. Turkey has been a sanctuary for the Syrian opposition, and the Turkish government has harshly criticized Assad's handling of the crisis.

In an emotional sermon carried live Monday on state television, Grand Mufti Ahmad Badreddine Hassoun, whose 21-year-old son died Sunday in an apparent ambush, lauded Assad. He said the Syrian president was a leader "who wants to guide Syria to victory, put the Syrian people on the path to victory, and give the homeland's sons the opportunity to be proud of their values, religion and Arabism."

The grand mufti's son was "assassinated by an armed terrorist group" on the road between Idlib and Aleppo, the government said.

Hassoun, recognized by the regime as the nation's top Sunni Muslim cleric, is a firm Assad ally. He declared that his son's killers "want Syria to kneel before Zionists and America," the official state news agency reported.

Most Syrians are Sunni Muslims. Assad and many high-ranking security officials are members of the minority Alawite sect, an offshoot of Shiite Islam. The nation also has a large Christian minority.

Anti-Assad activists answer the government's accusations by charging that authorities could be targeting prominent figures and then blaming their deaths on the opposition. The goal, antigovernment activists say, is to inflame sectarian tensions and bolster support among Syrians who fear the nation could descend into an Iraq-style civil war.

"What the regime is trying to do here is reinforce the sectarian story," Azm said by telephone from Ohio. "The regime wants to portray the uprising as a group of armed Islamic militants who are running amok in the country."

During more than six months of conflict in Syria, the United Nations says, about 2,700 people have been killed. The government says more than 700 security personnel have been killed.